At least one Australian, a Japanese and a German national were also among the 104 people killed in one of India's deadliest terrorist attacks. The Italian foreign ministry in Rome said an Italian was also killed.

The family of the dead Briton, who remains unnamed, have been informed, said the Foreign Office.

Britain's high commissioner in India, Sir Richard Stagg, said he had seen a number of injured British nationals in one hospital.

"I have seen myself three or four [injured Britons] and most of those have with them a partner of some sort who they are with. That's in one hospital.

"I think the number must be significantly more in total than that but I don't have an absolute figure at the moment," he told Sky News.

Earlier he said he knew of at least seven Britons wounded in the violence. India's government said 314 people were injured. Indian officials said eight militants were also killed.

An injured British survivor, Diane Murphy, 58, from Hexham, Northumberland, told how she and her husband were shot when they were in the Leopold cafe

"All of a sudden there was automatic gunfire," she said. "The whole place fell apart. It was tremendously loud. My husband and I were hit, as were lots of people.

"Everybody was down on the ground. The gunfire stopped for a few seconds then started again. We had to wait — it seemed like an age — for the police to arrive. I stayed with my husband because I could tell he was seriously injured. He was losing consciousness." Murphy's husband, Michael, 59, remains in intensive care.

Hostages are being held in the Oberoi hotel, which was one of the places attacked.

There are said to be more hostages in an office block in the city's financial district.

Stagg said he understood there was no longer a hostage crisis at the Taj Mahal hotel although a situation was continuing at the Oberoi. The hotels were among at least seven locations where westerners were believed to have been targeted.

Stagg said a reception centre was set up this morning for Britons who had been staying at the hotels and about 30 people had arrived in need of food, drink and accommodation.

"The crisis at the Oberoi hotel is continuing and I think the Indians have been focusing very much on bringing the terrorist incident to a conclusion and on getting the injured people to hospitals as quickly as possible.

"Those that I saw appeared to be being looked after well," he said.

Gordon Brown today offered India "all necessary help".

The prime minister said: "This is the loss of innocent lives, people just going about their daily business. We've got to do everything we can now to help."

A Foreign Office rapid deployment team, including two British Red Cross workers, flew to Mumbai today to help Britons caught up in the attacks.

UK police and security officials with anti-terror experience also travelled to India to support British High Commission staff and Indian officials if required.

A Foreign Office spokeswoman said: "A number of British nationals have been affected in these incidents.

"Staff at the deputy High Commission in Mumbai are attempting to contact British nationals believed to be in the area and are already in touch with a number of British nationals in the central hospitals of Mumbai.

"Our priority is providing assistance to them and contacting their families, and we will not be confirming numbers of those involved."

Sajjad Karim. Photograph: Matthew Fearn/PA

The British Conservative MEP Sajjad Karim, who was in the Taj hotel when it came under attack, said he fled to a "safe" basement as security forces fought gunmen "floor by floor and room by room".

"I left the Taj at 5am this morning and was taken to a secure place. The situation in the city is still ongoing but certainly at the Taj I think it is is over.

"I was in a room that was completely sealed off but I could hear what was going on.

Karim said the situation now was "very, very quiet".

Other British guests described the moment their hotels were stormed. Alan Jones, a businessman from south Wales, was in a lift at the Oberoi Trident when a fellow occupant was shot. There were frantic scenes as he tried to pull the man back in to close the door.

Alex Chamberlen, who works for a sports website and was in the city on business, told Sky News he believed the gunmen were looking for British and American visitors.

"They told everybody to stop and put their hands up and asked if there were any British or Americans. My friend said to me, 'Don't be a hero, don't say you are British.'"

The Federation of Tour Operators (FTO) said the "handful" of British nationals who booked a holiday in Mumbai through its members had been accounted for.

Andy Cooper, the director general of the FTO, said: "They have all been found and are safe."

The Foreign Office today advised against all non-essential travel to Mumbai until further notice. It said any British nationals in the city should stay indoors, monitor the media and not go out until local authorities advise it is safe.

· British nationals in the city who require immediate assistance have been told to call a special helpline: 0091-11 2419 2288.

· There is a UK number for those concerned about friends or family: +44 (0)20-7008 0000.

• This article was amended on Wednesday 30 July 2009. In the article above we quoted a man we said was called Alex Chamberlain. That should have been Chamberlen. This has been changed.